Frequency division circuit



July 2, 1935.

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FREQUENCY DIVIS ION C IRCUIT Filed Nov. 5, 1952 9 Sheets-Sheet 3 $INVENTOR.

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Patented July 2, 1935 UNITED STATES PATENT OFFICE] FREQUENCY DIVISION CIRCUIT Westley F. Curtis, Washington, D. 0. Application November 5, 1932', Serial No. 641,445

15 Claims.

(Granted under the act of March 3, 1883, as

amended April 30,

My invention relates broadly to frequency division systems and more particularly to a polyphase frequency division system.

One of the objects of my invention is to provide a system .of circuits for effecting a division in frequency of anflimpressed frequency simultaneously' with the multiplication of phase of the impressed frequency.

' Another object of my invention is to provide a relaxation circuit oscillator system having circuits connected in polyphase arrangement and adapted to'generate polyphase oscillations under control of single phase impressed. energy for effectinga division in frequency of the impressed energy.

Still another object of my invention is to provide a relaxation circuit oscillator system employing triodes connected in polyphasearrangement and having means for controlling the circuit connected with the control grids of the triodes from a single phase source whose frequency is to be divided for deriving a polyphase current at a submultiple frequency of the impressed frequency.

A further object of my invention'is to provide a relaxation circuit oscillator system employing tetrodes connected in polyphase arrangement and having means for controlling the circuit connected with the screen grids'of. the tetrodes from a single phase source which is to be divided in frequency and a submultiple of the impressed frequency obtained.

A still further object of my invention is to provide a relaxation circuit oscillator system employing tetrodes connected in polyphase manner with means for controlling the circuit connected with the control grids of the tetrodes for effecting a division in frequency of the impressed frequency.

Other and further objects'of my invention reside in the arrangement of a frequency division circuit ,as more fullyset forth in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 shows the circuit of my invention embodying a triode tube, with the plate elecrodes connected in delta and having impedance coupling between the output circuit of one tube and the input circuit of an adjacent tube, the con-' trol energy being applied to the control grid;

= Fig. 2 shows a modified form of the triode fre quency divider of Fig. 1, wherein the grid electrodes are connected in delta and the input and output circuits of adjacent tubes intercoupled through impedance coupling, the control currents being impressed upon the control grid for effecting the frequency division; Fig. 3 illustrates a Y-connested system wherein the plates are disposed in Y, and the grid electrodes are connectedin Y, with the output and input circuits of adjacent tubes coupled through an impedance coupling system, and the subharmonic frequency of polyphase characteristics derived in the output circuit upon the impression of the high frequency energy uponthe input circuit; Fig. 4 shows the circuit'of my invention wherein the triodes have their plates connectedin-delta and'the input and output circuits of adjacent tubes-coupledthrough resistance elements and arranged for the operation of the systemas a frequency divider; F-ig.-"5 shows another form of my invention wherein the grid electrodes are'disposed indelta andthe-input and output circuits of adjacent tubes intercoupled. through resistance elements, 'the control *currents being applied to the grid for deriving the sub-harmonic polyphase current in the output system; Fig. 6 shows a Y connected systeme'mbodying my invention wherein the plate electrodes are disposed in Y and the g rid'electrodes connected in Y, with the input and output circuits of the adjacent tubes coupled through resistances; Fig. 7 shows anarran'gement of" my invention in which the electron tubeshave their circuits connected in delta with the input and output circuits of adjacent tubes inductively coupled, the circuits being arranged to rec'eivehigh frequency energy and deliver a subharmonic polyphase current; the grid electrodes are connected in delta; Fig. 8 shows the triodes with their plate circuits arranged in delta, and the input and output circuits of adjacent tubes inductively coupled for establishing the oscillatory system which receives the high frequency energy and derives the sub-harmonic energy at polypha'se characteristics. I v v r c H Fig. 9 shows a Y connected system in whichtlie plate electrodes are connected in-Y and the grid electrodes connected in Y, with the input and output circuits of adjacent tubes inductively coupled and the circuits arranged for theim pression of high frequency energy on the control grid for deriving polyphase sub-harmonic energy in the output circuit of the several tubes; Fig. 10 shows an arrangement embodying the invention in which screen grid tubes are connected in a Y connected system, the grids being in'Y=, the

the input circuit of a succeeding v 'eieetmn time in the oscillator system; Fig. 11 shows a delta connected system having the input and output circuits of the tubes transformer coupled one to the other, with control on the screen grid for receiving a relatively high frequency and deriving a lower sub-harmonic frequency of three phase characteristic, the control grids are delta connected; Fig. 12 shows a further modified form of the circuit of the invention in which the screen grid tubes are connected. with their plates disposed in delta arrangement, the input and out-, put circuits of the tubes being inductively coupled; Fig. 13 shows a further modified form of the circuitof the invention employing screen grid tubes,

with the plate electrodes arranged in delta with control on the screen grid and having impedance coupling between the electron tubes; Fig. 14 shows another modified form of the circuit of the invention wherein the screen grid tubes are arranged with their circuits disposed in Y, that is, the plate circuits are connected in Y, the screen grid circuits upon which the control 'is impressed are arranged in Y, and the control grids are disposed in. Y, the control current being impressed upon the screen grid for deriving the lower frequency polyphase current in the output circuit, the output circuit of one electron tube being impedance coupled with the input circuit of the succeeding tube; Fig. '15 shows a further modified form of" the circuit of my arrangement, the grid electrodes being arranged in delta and the input and output circuits. of the adjacent tube being impedance coupled; the control current being applied to the screen grid of each of the tubes for deriving the sub-harmonic frequency from the impressed high frequency energy; Fig. 16 shows another modified form of circuit embodyingthe invention inwhich the screen grid tubes are arranged with their platecircuit connected in delta and thecircuits of one tube coupled to the circuits of an adjacent tube through a resistance coupling,the. control being applied to the screen grid in each instance for deriving the sub-har-' monic frequency from the impressed high frequency 'energy;'Fig. 17 shows another form of the invention in which the grid circuits are connected in delta and the adjacent tube interconnected through resistancev coupling with control potential applied to the screen grid; Fig. 18 shows a Y connected system wherein the screen grid tubes have their grids connected in Y, their plate electrodes connected in Y and the screen grids connected in Y, with theclrcuit of one screen grid tube. interconnected with the circuit of .an adjacent screen grid tube through resistance coupling and control potential applied to the screen grid of each of the tubes for deriving thesub-harmonic frequencyof polyphase characteristic; Fig. 19 shows a circuit arrangement embodying the principles of my invention in which the electron tubes have the plate circuit delta connected and thetube circuits are inductively coupled,"the control of the several circuits'being on the control grid; Fig. 20 illustrates amodified arrangement of the electron tube circuit wherein the electrodes of the tubes are'connected in Y' with impedance coupling between the several cirr cults of the electron tubes, with the control being upon the control grid of each tube; Fig. 21 shows a further modified form of the circuit of the invention in which resistance coupling is employed for interconnecting the several circuits of the tubes, the control being upon the control grid and thesystembeing wholly Y connected; Fig. 22 showsa further modified form of the circuit of theinvention wherein the control is upon the control grid and in which control is effected upon the control grid and the circuits of the several tubes are impedance coupled, the screen electrode being connectedin delta for establishing the oscillatory circuit for the conversion of the impressed high frequency energy into three phase energy of lower frequency; Fig. 23 shows an arrangement'of the electron tubes in the frequency division system of the invention wherein the control is applied to the. control grid, and the Screen grids of eachof the tubes are connected in delta utilizing resistance coupling; Fig. 24 shows a further modified form of the circuit of the invention wherein the screen grids of each of the tubes are connected in delta and the circuits of the several tubes inductively coupled for, establishingthe oscillatory path through the frequency division sys tem, the control for the several tubes being applied to the control grid; Fig. 25 shows a further modified form of the invention wherein a Y connected system for the grid circuitjand the plate coupling between the input and output circuits of each of 'the several tubes and control'applied to the control grid; and Fig. 27 shows another form of my invention with control applied to the control grids of the several tubes and the input and output circuits of the'tubes connected through impedance coupling means, with the plate electrodes connected in delta, the tube circuits being impedance coupled between the tubes; that is, be-

tween adjacent tubes, and not coupled between 1 r the input and output circuits of the same tube.

Summarizing the drawings, it will be observed that Figs. 1-9 show the frequency division system of my invention'in which a high frequency is impressed upon the input system and a three phase current of asub-harmonic frequency is obtained from the output side Figs. 10-18 show the frequency division system of my invention using tetrodes with the control on the screen grids; and Figs. 19 27 show the frequency division system of my invention employing tetrodes connected in polyphase arrangement with the control on the control grids whereby a single phase high nequency current is impressed'upon the three phase electron tube circuit and a. three phase low frequency current derived therefrom.

I have discovered that any electron tube amplifier, whether resistance, inductance, or transformer coupled, can be made to function as a relaxation oscillator by properly coupling the output'to the input, and that in general the number of phases produced by the oscillator can be made equal to the number of stages in the amplifier. Further, certain single-phase relaxation oscillators which do not. readily fall in the amplifier class can be adapted to'multi-phase operation;

Such an oscillator has many applications. First, it is capable ofproducing multiphase current of frequency J from single phase current of frequency nf, where n is an integer. This malt-i phase current may be utilized for driving a synchronous motor clock, for measuring the higher impressed frequency, or for controlling a syn-' trates triode tubes l, 2 and 3 having the plate electrodes lc, 2c and 3c thereof connected in delta through inductance elements I, 8 and. The I output circuit of one tube is impedance coupled to the input circuit of the adjacent tube. The single phase high frequency energy obtained from any suitable source such as represented at 4 is supplied to the input winding of the transformer 5. The output of transformer 5 is tuned by means of the variable condenser ii. The tuned circuit leading from condenser E connects to the control grid Ia of triode tube I and to the input circuit of the triode tube through impedance if}. The output circuit of triode tube l includes the inductance l and the source of potential. l l. Bypass condenser I la. is connected across the source of potential H. Condenser it connects between the input circuit of triode tube 9 and the output circuit of triode tube 3. Triode tube 2 has the output circuit thereof completed from anode through inductance 8 having a source of potential l3 in circuit therewith. Condenser Isa serves as a high frequency bypass condenser around thesource it. The input circuit of tube 2 includes impedance M. A condenser l5 connects between the input circuit of triode tube 2 and the output circuit of tube i. Triode tube 3 has its output circuit completed from anode 30 through inductance 9 and source of potential H5. Condenser I ia serves as a bypass for" high fre quency currents around source it. The input circuit of triode tube 3 includes impedance ll connected between the input and output circuits of triode tube 3 as shown. Condenser i8 connects between the input circuit of. triode tube 3 and the outputcircuit of triode tube 2. The delta arrangement of the anodes lo, 20 and 3c and the impedance coupling between the output circuit of one tube andthe input circuit of the adjacent tube with the control applied to the control grids Ia, 2a and 2b, enables the circuit to establish three phase oscillations which are controlled by the single phase oscillations impressed from the source upon the input circuit of the tubes for effecting a division in frequency and producing a sub-harmonic frequency delivered to the output circuit designated at 2!].

In Fig. 2 I have shown acircuit arrangement in which the control grids la, 2d and Ba of the triodes I, 2 and 3 are connected in delta with the input and output circuits of adjacent tubes intercoupled through impedance couplings, the control current being impressed upon one of the control grids for effecting the frequency division. The source of potential is impressed upon the illput circuit of triode tube I directly across impedance lil which connects to the input circuit of tube 1. Capacity coupling is provided as indicated at 19 between the potential source 4 and the input circuit of triode tube 1. The arrangement of the elements in the input and output circuits of the tubes is similar to the corresponding ly numberedparts illustrated in Fig. 1. The energy of divided frequency is delivered from the output circuit 20. I

In Fig. 3 I have shown the triodes arranged in a circuit with anodes la, 20 and 30 connected in Y. The grid electrodes la, in and 3a are likewise connected in Y with the output and input circuits of adjacent tubes coupled through an impedance coupling. The arrangement of the elements is similar to the arrangement illustrated in Figs. 1 and 2 except that in'the Y connected system a single'source of anode potential 2| is provided with inherent simplification. The source of input high frequency energy is shown at 4 capacity coupled through condensers l9 and resistance Bil to the control grids la, 2a and 3a through the common bus 22 and through resistors 23, 24 and 25 as shown. The anodes are connected through impedances 'l, 8 and 9 to common bus 25 which connects to the source of potential 2i. Condenser 3% is provided in shunt with potential source 2|. Condensers l5, l8 and I2 intercouple the input and output circuits of adjacent triodes. The high frequency energy supplied at M is subjected to a division in frequency delivcred at terminals 26.

It will be observed that I have shown inductance elements at I, 8 and 9; in the circuits of the triodes in Figs. 1, 2 and 3. I may employ resistance elements arranged in combination similar to the inductance elements of Figs. 1, 2 and 3 as will be understood more fully from a considcrationof Figs. 4, 5 and 6.

In Fig. 4 I have shown t -e triodes I, 2 and 3 having, their anodes connected in delta and the input and output circuits coupled through resistance elements arranged for the operation of the system a frequency divider. The output circuit of triode 1 includes resistance element 21. The output circuit of triode 2 includes resistance element The output circuit of triode 3 includes resistance element 29. The other elements in the circuit correspond to similarly numbered elements illustrated in Figs. 1, 2 and 3. I provide bypass condensers in shunt with the sources of potential as represented at Ha, 13a and Ida. I arrange condensers 33, 34 and 35 in shunt with resistance elements l8, I4 and I! in the input circuits of triodes I, 2 and}. respectively. I have shown the input potential from source A supplied through transformer 5 and tuning condenser 6 through the input circuit of trioole 3. The input potential may be supplied directly at the input circuit oiany one of the tubes in the polyphase circuit. The polyphase energy of divided frequency is delivered at output terminalsitl.

In Fig. 5 I have illustrated a form of my invention where the grid electrodes la, 2a and 3a are connected in delta. The input and output circuits of adjacent tubes are intercoupled to resistors 2128 and 29. The control current is applied from the single phase source 4 which con-. nects to the input circuit across grid lcand cath ode lb of electron tube l, which input circuit is shunted by resistance it. The remaining elements are arranged in a manner similar to the elements illustrated in Fig. 2 wherein the relaxation circuit condensers I2; lli an d I8 connect between the anode and control grids of the tubes in the manner shown. The sub-harmonic polyphase current is obtained in the output. circuit represented at if). i

Fig. 6 illustrates a circuit embodying my inven tion in which the plate electrodes of the tubes l, r and-3 are connected in Y and the grid electrodes also connected in Y with the input and output circuits of the adjacent tubes connected through resistances. The input circuit from source 4 is connected through condensers IS with resistance 60 which connects at one side to each of the controlgrid electrodes Ia, 2a and 3a through the common bus 22'and through resistors.23, 24 and 25 as described in connection with Fig. 3. The plate electrodes are connected in Y through resistors 21, 28 and 29 which are connected through the common bus 26 with the source of anode potential illustrated at 2|. The relaxation circuit charging condensers are represented at 12, .l5and #8. The polyphase sub-harmonic current is delivered at the output circuit shown at 20.

Fig. 7 shows another arrangement of the circuit of my invention in which the electron tubes I, 2 and 3 have their circuits connected in delta with the input and output circuits of adjacent tubes inductively coupled. The circuits are arranged to receive high frequency energy from the source and deliver a sub-harmonic polyphase current at the output circuit 28. The source 4 is connected through coupling condensers l9 across the grids of adjacent tubes. It will be understood that in this as in all forms of my invention, the source may be connected in any of the various ways shown in the drawings, such as between the control grid 3a of tube 3 and the opposite side of the input circuit of the tube 3 through inductance 3'! by means of coupling condensers or a coupling transformer. The input circuit of tube l includes inductance 38. The input circuit of tube 2 includes inductance 39. The output circuit of tube I includes inductance l which is inductively related to inductance 37. The output circuit of tube 2 includes inductance 8 which is inductively coupled with inductance 38. The output circuit of electron tube 3 contains inductance 9 which is inductively related to inductance 39 as shown. The sub-harmonic polyphase currents are delivered at circuit 20.

Fig. 8 shows a modified arrangement of my invention wherein the triodes have their plate circuits arranged in delta and the input and output circuits of adjacent tubes inductively coupled for establishing the oscillatory system which receives the high frequency energy and derives the sub-harmonic energy of polyphase characteristic.

In this arrangement the inductances 1, Band 9 are arranged in delta while inductances 31, 38

and 39 are each disposed in the input circuits of successive tubes and inductively coupled with the delta connected anode circuit windings. In'this arrangement the source 4 is connected through condensers IS with the grid electrode la of electron tube I and the cathode lb of electron tube I, thereby impressing the single phase high fre quency oscillations across the input of tube I while polyphase oscillations of divided frequency are derived from the output circuit 20. In each instance the inductances 1, 8 and 9 fix the time constant of the plate circuits of the tubes.

Fig. 9 shows a further modified form of the circuit of my invention wherein the plate electrodes of tubes I, 2 and 3 are connected in Y and the grid electrodesare connected in Y with the input and output circuits of adjacent tubes inductively coupled through transformer systems and the circuits arranged for the impression of high frequency energy on the control grids from the source 4 for deriving polyphase sub-harmonic energy in the output circuit of the several tubes from output circuit 20. In this arrangement tube 40;

and disposed in Y and respectively coupled with inductances 31, 38 and 38. The source'of potential 2| connected to bus 26 and to the common cathode connection; indicated at 10, provides means for energizing the plate circuits of all of e The condenser 36 connects I in shunt with the source of potential 2| as shown.

the electron tubes.

The high frequency energy impressed from source of potential 4 upon the circuits of the electron tubes is divided and a polyphase subharmonic current produced in the outputcircult 20. It will be observed that in all of the arrangements described in Figs. 1-9, the triodes are operated by control current applied to the control grids of the several tubes." 1 may provide ar rangements where tetrodes are employed in the frequency division system of the control cur rent applied to the screen grids as illustrated for example in Figs. 10-18.

Referring particularly to Fig. 10 I have shown tetrodes 40, 42 and 43 each including a controlas represented at 40b, an anode as represented at I 430, and a screen grid element as represented at The output circuits each include in Md. The screen grids are connected in Y. The

plate electrodes are connected in Y. The control current from the source 4 is impressed across the screen grid circuits. The output circuit of one electron tube is inductively coupled'to the input circuit of a succeeding electron tube in the oscillator system. That is to say the transformer 44 has its primary winding 44a connected in the output circuit of electron tube 4| and its secondary winding 44b connected in the input circuit of electron tube 43. Electron tube 43 has its output circuit coupled through transformer 45 with the input circuit of electron tube 42. Transformer 45 has its primary winding 45a connected in the output circuit of electron tube 43 and its secondary winding 45b connected in the input circuit of electron tube 42. The output circuit of electron tube 42 is coupled through transformer 46 with the input circuit of electron tube 40, that is primary winding 46a is disposed in the output circuit of electron tube 42 and secondary winding 46b is connected in the input circuit of electron 42d are connected to resistance elements 41, 48 and 49 with the common bus 50 whichv connects to one side of the input source 4. The opposite side of the input source 4 connects through the lead which extends to the point 5| nects in common to each of the cathodes 40b, 43b and 42b. The portion 52 of the battery 53 is utilized for applying a predetermined potential on each of the screen grids. The battery 53 is included in the plate circuits of all of the electron tubes. The polyphase energy of-reduced frequency is supplied tov the output circuit shown at 28.

11 illustrates a delta connected system for a set of tetrodes where the input and output circuits of the tubes are transformer connected which con-,

The screen grid elements 40d, 43d and The elements used acters. The impressed energy'in source 4 is ap-' plied to the input circuit of the'transformer 5 and impressed upon the screen grid electrode 42d of tetrode 42. The transformers M, 45v and 46 have their secondary windings 44b, 45b and 461) connected in delta and connected to the control grid electrodes 48a, 62a and 43a of each ofsthe tetrodes as shown. The output circuit of each tetrode extends from the anode of each tetrode through its associated primary winding as represented at Add, 450. and 45m In this arrangement each output circuit is supplied with an independent source of potential as shown at 54, and 5t. Oneach of these sources I provide taps 54a for applying predetermined potential to the screen grid electrode-43d, a tap" 55a for supplying predetermined potential to the screen grid electrode 42d and a tap 55a for applying predetermined potential to the screen grid electrode Md. The output polyphase energy of reduced frequency is delivered by circuit 21].

Fig. 12 embodying my invention wherein the screen grid tubes have their plate electrodes connected in delta and the input and output circuits of the tubes inductively coupled. I have employed reference characters similar to those shown-in Figs. 10 and 11 tov designate similar elements iri Fig. 12. It will be observed that the plate elec trodes "lilo, 43c and 420 are connected in delta arrangement. The transformers '44, d5 and 45 have their windings arranged for inductively coupling the input and output circuits of the several tubes. The centrol current is supplied from the source 4 through transformers 53, 58 and 551 as shown. The secondary windings of each of the transformers 51, 58 and Fi -connect with the'screen grid electrodes of each of the electron tubes as shown. A separate potential source is provided for each of the tubes 45, 62 and 43 by which the cathodes are heated, the required potential appliedtothe screen grids and the required potential supplied to the anodes. The polyphase energy of reduced frequency respect to the impressed frequency of the source 4 is delivered by output circuit 2e. I Fig. 13 illustrates a further modified-form of my invention employing screen grid tubes with the plate electrodes arranged in deltaand hav ing the control current supplied to the screen grid elements of the tubes, but have an impedance coupling between the input and output circuits of the tubes. The'input from source A passes through coupling condensers It and impedance 58 by which the control current is impressed upon screen grid electrode Add. The input of each tube is completed through impedance l9, II and H as illustrated. The impedance elements which are disposed in the delta connected circuit are similar to those employed in the arrangementof Figs. 1 and 2, and have been represented at 7, 8 and 9. Each electron tube is provided with an independent potential source as represented at H, l3 and it. The screen grid of each tube connects to a point on the-respective sources of potential as shown at 11b, 13b and I617. The potential to each of the screen grids is supplied through impedance elements which I have represented at 60, 6| and 52. The charging condensers employed in association with each of the relaxation oscillator circuits are represented at l2, l3 and 15. The energy of divided frequency is delivered at the output terminals 20. .1

' As represented in arranged with the plate circuits connected: in

shows a further circuit arrangement with Fig. 14 the tetrodes maybe Y, the screen grid circuits connected in'Y and the control grid circuitsconrieotedin'Y In thisarrangement the screen grids 4Udj42d and 43d are all shunted to the common bus 63. The control grid electrodes are connected-in a manner similar to the connectionof the control grid electrodes in Figs. Eand 6. That is, the control grids are bonded toe common bus Elthrough charging resistors 23, 24 and 25. Theoutput circuits are connected to a common bus 26 through induc tances E, 8 and din a manner similar to the ar-J rangement described in Figs; 3 and 6. A'com mon source of potential 53 is employedfor'en'ergisingthe screen grid ahdanode circuits of the several tubes. The section 52of the source 53 is employed for-energizing the screen grid electrodes.

i2, is and lit 'lhepolyphase enery of reduced' frequencyis delivered from output circuit 20 illustrated. I In Fig. 15 I have shown a circuit arrangement where a'grid electrode of the tetrodes are con nested in delta and the input and output circuits of adjacent tubes coupled through 'impedances, the control current being supplied to the screen grid of one of the tetrodes at single phase beingmodified to obtain a polypha'se current of reduced frequency at the output terminals of the apparatus. upon screen grids 4fld, 43d and Md. The im-' pedance elements I, 8 and 9 are arranged in a manner similarto'the impedance elements in Fig, 2. The input circuit of each tube isclosed through impedance I0, [4 and IT. Proper bias potentials on the screen grids are obtained from sources ll, l3 and i6 through taps lib, I31) and Mil). The charging resistances are shown 'for'. tubes 42 and 43 at 62 and BI respectively. The charging condensers are shown at i2, Hand 18; Figpl'fiv shows a modified form of the'circuit of my invention wherein the screen grid tubes M1, 42 and 43' havetheir plate circuits connected in delta and the circuits of one tube coupled to, the circuits of an adjacent'tube through a resistance coupling where the control current is applied to, the screen grid electrodesf The screen grid electrodes are designated at 40d, 42d and 43:1,, one of them, namely Md, being energized from source 4- connected across resistance 60. The resistance, elements .fi'i, Eli'and 29 are arranged in a manner similar to the arrangement described in connection with Fig. 4 for providing a delta circuit with respect to the plate electrodes of each of the ubes. The charging condensersforvthewrelaxation circuit oscillator system are shown at [2,15 and 18. The polyphase current ofreducedfrequency is delivered at output terminals 20.

In Fig. 17 I have shown a circuit arrangement fortetrodes wherein nected in delta and the adjacent tubes interconnec'ted through resistance elements, the control potential being supplied to the screen gridelectrodes. In this arrangement the control grids- 43a, 43a and 420, are connected indelta as shown. The potential supplied from source 4 through coupling condensers l9 and resistance is im-ix upon the screen grid 40d,- in the'mann'er- In order to provide for the properpothe screen grid'electrodes I pressed shown. tential on each of have. shown auxiliary potential sources at 64,

. I'n Fig..181I metastases sat-a1 aga nst The charging condensers'are shown at' and The input current is impressedv the grid circuits are'confore explained'for establishing a Ycon'nected circuitfor the screen grid electrodes.

grids of all or the tubes.

. V tThe control grids are connected to J are' coupled to the impedancesl, 8 and 8.

- where the screen grids areiconnected in Y,' the plate electrodes connected in Y and the control grids connected in Y but having the adjacent circuits of the tubes connected through resistance elements and the; control potentialapplied to the screen grids of each of the tubes. In this arrangement I have shownthe source 4 connected-through coupling condensers I9 to the selector circuit 61 and to the screen gridcircuit of the several tubes through the common bus 63. The portion 52 of battery 53 is employed for biasing screen grid electrodes. The plate electrodes are connected in Y through resistance elements 21, 28 and28'which connect to the common bus 26. The control grid electrodes connect through resistors 23, 24 and 25, constituting the charging resistors in this particular embodiment of the invention, to the common bus 22. The screen grid electrodes "48d, ,42d and 43d connect through biasing resistors to the common bus 63 as hereto- I'he charging condensers for the relaxation oscillator circuit are indicated at I2, l5 and I8- The subharmonic frequency of polyphase characteristic is delivered to'the' output circuit represented at 2B.

'In Figs. 19-27 I have illustrated circuit'arrangements forithe frequency division system of my invention wherein tetrodes are employed connected in three phase relation with the control current applied to the control grids of the te trodes as distinguished ,-from the application of the control current to the screen grids as set forth in Figs. 1018.

- In Fig; 19 the tetrodes 40, 42 and 43 have the plate circuits thereof connected in delta and the input and output circuits of the tube inductively coupled. 'The control current is applied to the;

control grids 48a, 42a and 43a. The plate circuits are each connected to separatesources of potential represented at H, l3 and I6. The

plate circuits are connected in delta and connected to the output terminals indicated at 28. The input circuit is supplied to each of the control grids throughtransformers 51, 58 and 59 which have their primary windingsconnected in series and each of which have secondary windings individual to the control'grid circuits of each of the tubes. The screen grid circuits which extend from screen grids 48d, 42d and 43! each include a coupling inductance constituting the primary winding of the coupling transformers. The coupling transformers are shown at 44, 45 and 46. The primary windings are connected in the screen grid circuits and the secondary windings are con-' nected in the delta connected output circuit as shown.

In Fig. 20 I have shown a modified arrangement in which the'tetrod'e's 40, 42 and 43 have their elements connected in Y with impedance couplingmeans between the several circuits or the tetrodes and with the control current impressed upon the control grid ofeach of the'tetrodes.

The input circuit from source 4 connects to potentiometer 68, the opposite ends of which are connectedacross the cathode and control The cathodes are con nectedin Y at the common point 10 as shown. resistors l8,

'l4 and l1 to the other side of the potentiometer 88. The plate electrodes 48c, 420 connected'in Y into the output circuit 28 for "delivering polyphaseener'gy at divided frequen tubes and 430' are cies.. The input and output circuits of the The charging condensers for the relaxation circuit are shown at l2, l5 and I8.

In Fig. 21 I have shown a, circuit similar to the circuit illustrated in Fig. 20 except that resist ance elements 21, 28 and28. are employed for interconnecting the several circuits of the tubes 40, 42 and 43. The control current is supplied to the control grids a, 42a and 43a. through resistors I 0, I1 and I4. The screen grids 40d, 42d and 43d are connected to the point of intermediate potential on source 53 through resistors ll, 12 and 13. The charging condensers for the relaxation oscillator circuit are shown at l2, l5 andl8.

Fig. 22 shows a circuit arrangement for the frequency guider of my invention where the circuits of the tubes 40; 42 and 43 are impedance coupled. The screen electrodes 40d, 42d and 43d are connected in delta. The control current is'supplied from source 4 to the transformers 54, 58 and 51 to the control grids 40a, 42a and 4311. Each of the output circuits includes a coupling inductance I, 8 and 9 connected .in circuit with independent sources of potential ll. I3 and It. The charging resistances are shown at ll, '12 and 73. The charging condensers are shown at l2, l5 and I8. The polyphase output current is delivered to the terminals 20 at a divided frequency with respect to the frequency of the input current at terminals 4.

In Fig. 23 I have shown a circuit arrangement similar to the circuit arrangement shown in Fig. 22 except that-resistance elements are used instead of impedance elements for the several tubes,

The resistances illustratedat 21, 28 and 29; serve as coupling means for the tube circuits. The remaining elements describedin connection with Fig. 22 are employed in a similar relationship in the circuit of Fig. 23.

In Fig. 24 I have shown a further modified form of my invention wherein the screen grids 40d, 42d and 43d are connected in delta and'the circuits of the several tubes inductively coupled by means of transformers 44, 45 and 46 for establishing the oscillatory path through the -fre- The control current for In Fig. 25 a further modified form of the system I of my invention is employed whereina Y connected circuit for the control grids, a Y connected circuit for the plate electrodes and a Y connectedcircuit for the screen grids are provided with the 1 control current applied from the source 4 to the control grids. I have shown the control grids III while the lower end 48a, 42a and 43a connected'to the upper potenf tial end of potentiometer of the potentiometer I8 is connected through bias-,- ing source 14 to the common cathode connection 18. The plate and screen grid electrodes have their circuits coupled through transformer 44, 45 and 46', the respective windings being connected in Y. The common potential source 53 is provided with a tap thereon for supplying interme-'; diate potential to the screen grid electrodes 48d, 42d and 43d. The nolyphasegenergy of divided.

frequency is delivered to output terminals 29.. In Fig. 26 I have shown a circuit arrangement where the plate electrodes are connected in delta with resistance coupling between the input and output circiuts of each of the tubes. The resist ance coupling has been shown at 21, 28 andiit connected with the plate circuits of the tubes which are disposed in delta. The charging resistances are connected in the screen grid circuits and are shown at I I, I2 and 13 connected to points of intermediate potential in the plate circuit sources ll, l3 and E6. The charging condensers are shown at l2, l5 and H3. The control grid is introduced through the control grid circuits in each of thetransformers 5 6, 51 and 58. Suitable potential sources are applied to each of the input circuits for biasing the control grids atselected potentials. I Fig. 2'? shows a form of my invention in which the input and output circuits of the tubes are coupled through inductance elements I, 8 and 9 with the plate circuits of the tubes connected in delta and the control current applied to the control grids. The input current from the source 6 leads through transformers 54, 51 and 53 to the control grids Mia, 42a and 43a of the tetrodes. "The plate electrodes are connected in delta and include inductance elements I, 8 and S in circuit with the independent sources of potential ll, l3 and It as shown. The charging resistances are shown at l E2 and 13. The charging condensers are indicated-at l2, l5 and i8. The polyphase energy ofidivided frequency is delivered at output terminals 20. I

. I have found the several embodiments of my invention practical in assembly and operation. I have successfully effected frequency division of an impressed frequency of twenty-five kilocycles to derive three phase energy at one kilocycle. While I have set forth many of the preferred embodiments of my invention I desire that it be understood that other combinations of ele-- ments may be employed and that the circuits il lustrated are not to be considered in a limiting sense but as illustrating various forms of my invention. No limitations upon my invention are intended other than are imposed bythe scope of the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a frequency division system, a multiplicity of electron tubes, circuit means interconnecting said tubes in polyphase relationship and having an input and an output circuit, means for impressing single phase current of a predetermined frequency on said input circuit and means included in said circuit means for deriving at said output from said multiplicity of electron tubes connected in polyphase arrangement, a polyphase current having a frequency which is a sub-multiple of the impressed frequency.

2. In a frequency division system, circuit means including an input circuit and an output circuit, a multiplicity of electron tubes interconnected by said circuit means in Y formation, means for impressing single phase current of a predetermined frequency on said input circuit, and means included in said circuit means for deriving from said output circuit a. polyphase current having a frequency which is a sub-multiple of the impressed frequency.

3. In a frequency division system, circuit means including an input circuit and an output circuit, a multiplicity of electron tubes connected by said circuit means in delta formation, means for im pressing singlephase current of a predetermined frequency on said input circuit, and means included in said circuit means for deriving from said output circuit a polyphase current having a fre quency which is a sub-multiple of the impressed frequency.

4. In a frequency division system, circuit means including an input circuit, a multiplicity of electron tubes connected in polyphase formation by said circuit means, each of said tubes including a control electrode connected with a condenser and a resistance, an output circuit included in said circuit means and connected with said electron tubes, means for impressing single phase current of a predetermined frequency on said input circuit, and means for deriving from said multiplicity of electron tubes connected in polyphase arrangement, a polyphase current having a frequency which is a sub-multiple of the impressed frequency. Y

. 5. In a frequency division system, circuit means includingan input circuit, a multiplicity of electron tubes connected in polyphase formation by said circuit means, an output circuit included in said circuit'means and connected with said electron tubes, impedance elements for coupling the input electrode of one tube and output electrode of another tube in a reentrant cascade formation, means forimpressing single phase current of a predetermined frequency on said input circuit and an output circuit included in said circuit means and connected withsaid multiplicity of electron tubes for delivering polyphase current having a frequency which is a submultiple of the impressed frequency.

6. In a frequency division system, circuit means including an input circuit, a multiplicity of electron tubes connected by said circuit means in polyphase formation, an output circuit included in said circuit means and connected with said electron tubes, means for coupling the input and output electrodes of each of said electron tubes, and means included in said circuit means. for impressing single phase current of a predetermined frequency on said input circuit for delivering at said output circuit polyphase current having a frequency which is a sub-multiple of the impressed frequency. v

'7. In a frequency division system, circuit means, a multiplicity of electron tubes connected by said circuit means in polyphase arrangement, an input circuit included in said circuit means and connected with the control grids of said electron tubes, an output circuit included in said circuit means and connected with said electron tubes, said circuit means coupling. the input and ity of tetrode electron tubes each including a1 7 control grid, a screen grid, a cathode and an anode, circuit means interconnecting said tetrode electrontubes in polyphase arrangement, an input circuit connected with the control grids of said tetrode electron tubes, an output circuit connected with said tetrode electron tubes, means coupling the input and output circuits of each of said tetrode electron tubes in reentrant cascade, means for impressing single phase current of a predetermined frequency on the control grid circuits of said tetrode electron tubes, and means for deriving polyphase current in said output circuit having a frequency which is a sub-multiple of the impressed frequency.

9. In a'frequency division system, a multiplicity of tetrode electron tubes each including a control grid, a screen grid, a cathode and an anode, means interconnecting the electrodes of said tetrode electron tubes in polyphase arrangement, an input circuit connected with one of the electrodes of each said tetrode electron tubes, an output circuit common to all of said tetrode electron tubes, means for impressing single phase current of a predetermined frequency on the screen grids of said tetrode electron tubes, and means for deriving a polyphasecurrent having a frequency which is a sub-multiple of the impressed frequency in the output circuit of, said tetrode electron tubes. I 7

10. In a frequency division system, a multiplicity of tetrode electrontubes each having a screen grid, a. control grid, a cathode and'an anode, circuit means intercoupling the input and output circuits of each of said tetrode electron tubes in delta formation, an input circuit included in said circuit means connected with said control grids for impressing single phase current on said circuits, an output circuit included in said circuit means common to'sa'id tetrode electron tubes, and means for deriving in said output circuit a polyphase current having a frequency which is a submultiple of the impressed frequency.

11. In a frequency division system, a multiplicity of tetrode electron'tubes each having a screen grid, a control grid, a cathode and an anode, circuit means intercoupling the input and output electrodes of each of said tetrode electron tubes, circuits interconnecting said tetrode e1ectron tubes in Y formation an input circuit included in said circuitmeansand connected with said control grids for impressing single phase current on said circuit means, an output circuit included in said circuit means and commonto said tetrode electron tubes, and means 'forderiving in said output circuit a polyp-hase current having a frequency which is a sub-multiple of the impressed frequency.

12. In a frequency division system, circuit '1 means a multiplicity of tetrode electron tubes each having a. screen grid, 2, control grid, a, cathode and an anode, impedance elements included in said'circuit means and interconnecting the in-,

put and output circuits of each of said tetrode electron tubes, said circuit means interconnecting said tetrode electron tubes in delta, an input circuit included in said circuit means and connected with one of the gridsof each said tetrode electron tubes for impressing single phase current upon said circuits, an output circuit included in said circuit means and common'to all of said tetrode electron tubes, and means for deriving in said output circuit a polyphase current which is; a sub-multiple of the impressed frequency.

13. In a frequency division system, circuit means, amultiplicity of tetrode electron tubes each having a screen grid, a control grid, a cathode and an anode, means included in said cir circuit meansintercoupling the input and output circuits of each of said tetrode electron tubes, circuit means interconnecting the electrodes of said tetrode electron tubes in Y formation, an input circuit included in said circuit means and connected with the control grids of said tetrode electron tubes for impressing single phase current on said circuits, an output circuit included injsaid circuit means and common to said tetrode 'electron tubes, andmeans for deriving in said output circuita polyphase current having a frequency which is a sub-multiple of the impressed frequency. 7

14. In a frequency division system, circuit means, a multiplicityof tetrode-electron tubes each havinga screen grid, a control grid, a cathode and an anode, circuits included in said circuit means for intercoupling the input and output circuits of each of said tetrode electron tubes, said circuit means interconnecting said anodes in Y, said control grids in Y, and said screen grids in Y, means included in said circuit means and interconnecting said control grids andsaid anodes, an input circuit for impressing. single phase current on said control grid electrodes, an output circuit common to said tetrode electron tubes, and means for deriving in said output circuit a polyphase current having a frequency divided with respect to the impressed frequency.

15. Ina frequency division system, circuit means, a multiplicity of tetrode electron tubes each having a screen grid, a control grid, a cathodeand an anode, said circuit means intercoupling the input and output circuits of each'of said tetrode electron tubes and interconnecting said tetrode electron tubes in delta,-a charging circuit comprising a condenser and an impedance in cluded in said circuit means and connected with each of said tetrode electron tubes for establish ing a relaxation, circuit oscillatory path for the production of polyphase currents, an input circuit included in said circuit means and connected 

